Now it's turned into a scene, with dozens of media members showing up for a morning shootaround before a meaningless final Dallas home against Denver on Tuesday night, with both teams eliminated from the playoffs.
Romo's "Mav for a day" experience came exactly a week after it was announced that he was leaving the Cowboys and joining CBS as the No. 1 NFL analyst. He lost his job as the Dallas starter to Dak Prescott last season and chose TV over pursuing a starting job with another team with his 37th birthday approaching next week.
"At first, I was just feeling like I didn't deserve any of that," Romo said of his initial first reaction to the offer. "Standing here today, I feel a little embarrassed to be honest in the sense that you're lucky enough to be in position, that someone cares enough to do something to honor you."
But Romo said it was a "no-brainer" to accept the offer of a tribute from Nowitzki and Mavericks coach Rick Carlisle. He will be in uniform in his football No. 9 and go through pregame warmups and introductions. Carlisle said Monday that Romo wouldn't play.
When the shootaround was over, a member of the Mavericks staff whistled a circus theme song while walking past reporters. On the court, Romo was playing with his youngest son, Rivers.
A long line of media members followed Romo off the court, then filled the room where Carlisle does his game-day interviews.
"I had close to 600 text messages that I'm still working on," said Romo, the all-time leader in yards passing and touchdowns for the storied Cowboys franchise but lacking a Super Bowl title. "And 100-some calls and a bunch of other stuff.
"I guess it just makes you feel that you accomplished something in some ways. I feel like I left something out there that I always wanted to accomplish. I've got to live with that and that's part of playing sports."
Carlisle said Romo would be in the group text that sends pregame shooting times to all the players, and the plan was to include Romo in at least one team photo since his honorary day was also the team's picture day. He also has a locker .
"He has stood for all of the things that great Dallas athletes stand for," Carlisle said. "Great competitor, winner, plays hurt, the whole thing. And he's been a great supporter of the Mavericks and a good friend. We wanted to see if he would be willing to do this."
Romo was a high school basketball standout in Wisconsin and played against Caron Butler, who spent 14 years in the NBA through last season. Butler was on the Dallas roster but injured when the Mavericks won their only championship in 2011.
"I'm gonna score 20," Romo joked.